1.檢查是否安裝apache
    rpm -qa | grep apache
    或 rpm -qa | grep httpd
    
    卸載apache
        rpm -e gnome-user-share-2.28.2-3.el6.i686
        rpm -e httpd-2.2.15-5.el6.centos.i686
        rpm -e httpd-tools-2.2.15-5.el6.centos.i686
    重啟是否看是否影響系統運行
2.安裝依賴軟件
    (1)下載APR和APR-util(apr.apache.org)
        解壓并將其復制到$APACHE_SOURCE_LOCATION/srclib/apr
        注：復制，目標文件夾不包含版本號
        cp -r apr-1.4.6 httpd-2.4.1/srclib/apr
        cp -r apr-util-1.4.1 httpd-2.4.1/srclib/apr-util
    (2)安裝perl-compatible Regular Expressions Library
        ./configure --prefix=/usr/local/pcre
        make
        make install
3.下載apache httpd
    ./configure --enable-so --with-included-apr --with-pcre=/usr/local/pcre
    make
    make install
4.測試是否安裝成功
    ./apachectl -k start
    在瀏覽器地址欄輸入：http://localhost；看見It works!，表示安裝成功。
    ./apachectl -k stop